The present invention relates to semiconductor fabrication apparatus such as epitaxial growth systems or the like.
The ordinary epitaxial growth systems are equipped with a process chamber, into which a reactant gas is introduced and which is provided with a susceptor for supporting a semiconductor wafer, and a driving unit for rotating this susceptor. This driving unit is, for example, a unit in which a driven part consisting of a magnetic material is fixed to lower part of a support shaft supporting the susceptor from the bottom and in which an annular member with a plurality of magnets arranged at predetermined intervals is placed outside (or around) the driven portion. This annular member is connected to a motor.
In the system of this structure, when the annular member is rotated by the motor, magnetic attraction and magnetic repulsion acts between the magnets and the driven portion. As a result, the driven portion rotates in response to the rotation of the annular member, whereby the susceptor rotates through the support shaft.
Incidentally, deposition processes in the semiconductor fabrication apparatus such as the epitaxial systems or the like employ a corrosive gas such like chlorine-based gas as the reactant gas, which can corrode the member made of the magnetic material and other members. In many such conventional systems, the surface is treated by a surface treatment of nickel plating or the like in order to prevent the corrosion of the driven portion.
However, the inventors investigated the conventional systems and found that the magnetic material of the driven portion did not always have sufficient corrosion resistance and there were desires for further improvement.
Therefore, the present invention has been accomplished under such circumstances and an object of the invention is to provide a semiconductor fabrication apparatus improved in corrosion resistance of the magnetic material and a fabrication method thereof.
In order to accomplish the above object, a semiconductor fabrication apparatus according to the present invention comprises a process chamber into which a reactant gas is introduced and which has a pedestal for supporting an article to be processed, and a pedestal drive for rotating the pedestal; the pedestal drive comprises a shaft member which is coupled to the pedestal and which comprises a driven portion mainly comprised of a magnetic material, and a member which has a plurality of magnets arranged outside the driven portion and which can rotate the driven portion; and the driven portion has a metal coating on a surface of the magnetic material and a metal oxide film on the metal coating.
In other words, the semiconductor fabrication apparatus of the present invention is a semiconductor fabrication system comprising the process chamber into which the reactant gas is introduced, the pedestal for supporting the article, which is disposed in the process chamber, and the pedestal driving means (drive) for rotating the pedestal, the pedestal driving means comprising the shaft member coupled to the pedestal and having the driven portion of the magnetic material, and the member placed outside the driven portion and having a plurality of magnets for imposing a rotational force on the driven portion, wherein the metal coating is formed on the surface of the driven portion and the metal oxide film is further formed on the metal coating.
When the metal oxide film is formed on the metal coating laid on the surface of the driven portion in this way, for example, by a passivation treatment, dissolution, reaction, or the like of the metal coating becomes hard to occur, which improves the corrosion resistance of the magnetic material forming the driven portion.
It is preferable to form the metal oxide film by reaction of the metal coating with ozone. Namely, the metal oxide film is preferably a film formed by combination of the metal coating with ozone. This permits the metal oxide film to be formed on the metal coating at ordinary temperature (for example, at or below 30xc2x0 C.), thereby decreasing variation in magnetic characteristics of the magnetic material.
Further, the metal coating is more preferably a coating containing at least either one of nickel and chromium. Particularly, the metal coating is more preferably made of at least one of a nickel coating and a chromium coating. In this case, for example, the surface of the driven portion is given nickel plating and this nickel plating is covered by chromium plating. This can prevent the corrosion of the driven portion at relatively low cost.
A method of fabricating the semiconductor fabrication apparatus according to the present invention is a method of effectively fabricating the semiconductor fabrication apparatus of the present invention. Namely, the method is a fabrication method of a semiconductor fabrication apparatus comprising a process chamber into which a reactant gas is introduced and which has a pedestal for supporting an article to be processed, a shaft member which is coupled to the pedestal and which has a driven portion mainly comprised of a magnetic material, and a member which has a plurality of magnets arranged outside the driven portion and which can rotate the driven portion (or which can impose a rotational force on the driven portion), the fabrication method comprising forming a metal coating on a surface of the magnetic material and further forming a metal oxide film on the metal coating.
Specifically, it is preferable to form the metal oxide film by supplying ozone onto the metal coating to bring about reaction between the metal coating and the ozone. Further, it is more preferable to form the metal coating by depositing a film containing at least either one of nickel and chromium on the surface of the magnetic material.